Video is a great tool for showcasing your expertise and positioning yourself as the natural expert in your field, and technology has made it easier than ever to get the videos you create in front of your target audience.
I'm a great fan of video - it's why I have so many on my youtube channel (www.youtube.com/robcuesta), on my facebook page (http://www.facebook.com/6FigureBlueprint) and in the member's area of www.PracticeMomentum.com.
So I'm always on the lookout for great examples that we might not otherwise see.
I just finished watching The Conspirator - a movie about the trial of Lincoln's assassins.
Watching the "extras" it became obvious that this film was made with love, care, and attention to detail by a group of very highly knowledgable experts. There are ten featurettes - each only a minute or so long - that each highlight a different area of expertise.
If you want to see how to show your audience how much you know without being salesy or pushy, I really recommend that you rent the DVD and watch the extras.
Oh and the film is great too :)